Valve systems are used to transmit pressurized fluids or liquids from one container to another container, especially when the pressurized liquids are corrosive, toxic or environmentally unsafe. With such systems, for example, a hose valve for transmitting the pressurized fluids is threadably connected to a filler valve of a container or tank so that a fluid passageway exists when the valves are open allowing liquids to freely pass. A second set of valves are normally connected allowing vapors to freely return to expedite the filling procedure. Prior to disengaging the valves, each valve must be closed off and the passageway between each valve sealed so that no liquid is emitted to the atmosphere when the joint between the valves is disconnected. Because of the toxicity, corrosiveness or otherwise environmental unsafeness and destructiveness of the cumulative effects of these liquids and vapors, even minute amounts are considered harmful and undesirable.
Prior to this invention, valves were closed in the following manner: the valve poppet had an O-ring fitted around the poppet. The valve was considered closed when the O-ring sealed and came to rest against the valve seat. However, the valve seat was not completely evacuated prior to sealing, because the poppet and valve seat were not designed for complete evacuation and the procedure used was the single step of simultaneous closing and sealing of valves.
Unfortunately, these prior valve systems allowed small quantities of liquids to become trapped within the passageway between the two valves because the compressible valve seals hit the inner walls of the valve bodies causing a seal before fluids were completely evacuated and a proper sequence was not followed for evacuating abutting valves. Minute amounts of fluid were thereby trapped within the sealing area which were later emitted when the valve joint was disconnected. Although the amount of fluid is minute, each time a valve is disconnected these minute amounts of toxic, corrosive or otherwise environmentally unsafe or destructive liquids are emitted to the atmosphere. Repeated engagement and disengagement of millions of hose and filler valves throughout the chemical and petrochemical industries can substantially add unwanted pollutants to our already endangered atmosphere.